Self-priming centrifugal pump



May 14, 1957 w. E. RUPP 2,791,968

SELF-PRIMING CENTRIFUGAL. PUMP Filed Sept. 8, 1953 INVENTOR. WARREN E.PUFF A TTOENEYS United States Patent C l SELF-PRIIVIING CENTREFUGALPUMfP Warren E. Rupp, Mansfield, Ohio, assignor to The Gorrnan-RuppCompany, Mansfield, Ghio, a corporation of Ohio Application September 8,1953, Serial No. 378,959

6 Claims. (Cl. 103-113) This invention relates generally to the art ofcentrifugal pumps and is particularly concerned with self-primingcentrifugal pumps having a new mode of operation and the new result ofmuch more rapid priming action than is possessed by conventionalself-priming centrifugal pumps.

In all self-priming centrifugal pumps with which I am familiar, primingis accomplished by mixing liquid and gas in the impeller chamber anddischarging that mixture, thus gradually exhausting the gas from theimpeller chamber and the line leading thereinto and filling them withliquid. During such priming action the impeller delivers a stream ofsuch mixture containing much less liquid than is present after priminghas been completed, and hence during the priming action the liquiddelivered by the pump is less than after priming has been completed.Thus the centrifugal pump is quite efficient while pumping but isrelatively inefficient for pumping while priming.

The so-called jet ejectors are more eflicient as priming means but lesseflicient as pumping means than centrifugal pumps. Since the function ofa jet ejector is primarily that of priming, jet ejectors have been usedin conjunction with centrifugal pumps for priming where greater primingspeed is desired than can be furnished by a centrifugal pump alone.

There has long existed a demand for a centrifugal pump, which wouldprime much more rapidly than conventional pumps and at a speed favorablycomparable to a pump and jet ejector combination, but none has beenproposed heretofore which would meet those demands so far as I am aware.That demand is satisfied by the present invention.

One illustration of a use where a rapid priming action is essential iswhere high test gasoline is to be pumped out of drums and into the tanksof airplanes. Commercial centrifugal pumps are not satisfactory for thispurpose for they require much more time to prime the suction hose andimpeller chamber than to pump the 55 gallons of gasoline contained in adrum. The present invention makes it possible to deliver almost acontinuous stream of such gasoline as drum after drum is being emptiedbecause of the extremely short time required to do whatever priming isrequired as the hose is moved from one drum to another.

Another illustration of a use demanding rapid prim? ing action is wherecondensate is to be pumped, for example in a so-called vacuum heatingsystem. There the pump must continuously handle large volumes of vaporand liquid and very little time is permitted for priming action. Thepresent invention is quite satisfactory for such a use because of itsextremely rapid rate of priming.

Still another use where rapid priming is demanded is in connection withdrainage operations where the level of an underground water table is tobe lowered. For this purpose well points i. e., pipes havingperforations at the lower ends, are sunk into the ground approximatelyto the desired level of the water table and a plurality of such pipes isconnected by headers to a centrifugal pump 2,791,968 Patented May 14,1957 which is to pump out the water to lower the surface of the watertable to the predetermined level. Present day self-priming centrifugalpumps do not have sufiicient air handling capacity to remove the airfrom these pipes rapidly or efiiciently, and as a result special wellpoint pumps have been developed to handle the large volume of air. Thepresent invention makes it unnecessary to use such special well poinpumps for pumps embodying the present invention have the necessary largeair handling capacity.

The present invention will be better understood by those skilled in theart from the drawings accompanying and forming a part of thisspecification and in which:

Fig. 1 is a diagrammatic, vertical, center view through one form ofapparatus embodying the present invention.

Fig. 2 is a view similar to Fig. 1 by showing a modified form of theinvention, and,

Fig. 3 has a view similar to Fig. 1 by showing still another modifiedform of invention.

In Fig. 1 the pump housing 1 is adapted to contain fluid indicated at 2,and is provided with a fluid inlet 3. A casing 4 is disposed withinhousing 1 which has an inlet 5 communicating with inlet 3 of housing 1so that gas and liquid may flow from that inlet and any pipe or hoseconnection associated therewith (not shown) into the interior of easing4. This casing 4 also has an inlet 6 for a liquid within the housing.Casing 4 comprises opposite side walls 7 and 8, the former defininginlet 5 and the latter defining inlet 6, and has a peripheral wall 9connecting the peripheries of side-walls 7 and 8 and partly defining twochambers Ill and 11 and a Venturi-like outlet 12, communicating withboth of said chambers. Within casing 4 a partition Wall 15, extendsparallel to and approximately midway between side-walls 7 and 8, and isintegrally connected to wall 9. In approximate alignment with Venturi12, the partition wall 15 is shaped to define a nozzle 16, and isconnected to side-wall 8 adjacent to the nozzle as at 17. It will beunderstood that the two chambers 10 and 11 provided in casing 4 maycornmunicate with each other at the outlet of nozzle 16, and that thisnozzle and Venturi 12 are in substantial alignment so that liquiddelivered through nozzle 16 will be projected into Venturi 12.. A shaftsupport 20 is secured to the side of housing which is opposite to theinlet 3 and an impeller shaft 21, is rotatably mounted in bearings 22,carried by support 20. This shaft may be rotated by a belt (not shown)running over pulley 23, attached to shaft 21, or by any other suitableand conventional means. Shaft 21 extends through packing 25, and apacking gland at 26, which surround a hole in the side of housing Whichthrough the shaft extends. The inner end of the shaft may be rotatablysupported by bearing 27 in partition wall 15. An impeller 30 is disposedin chamber 1t and is fixed to 'the end of shaft 21, and an impeller 31,is disposed inchamber 11 of easing 4, and is also secured to shaft 21.

The operation of the apparatus shown in Fig. 1 is substantially asfollows: assuming that housing 1 contains liquid substantially asillustrated in .Fig. 1, and the pump is to pump liquid, the shaft 21 isrotated. Impeller 31 pumps liquid 2 into chamber 11 and discharges itthrough nozzle 16 through Venturi 12 into the space above the liquidlevel in housing 1. The action of the liquid passing under high velocitythrough Venturi 12 is to draw gas from within chamber 10 and inlet 3through impeller 30 and discharge it through that Venturi. This gas willseparate from the liquid promptly after delivery into the upper part ofhousing 1, and the gas may escape from the housing through outlet 35while the liquid may return for recirculation through impeller 31 andVenturi 12. As this action continues the gas is rapidly exhausted fromchamber 10, inlet 3, and any pipe connecting therewith on the principalof a jet ejector, and thus the rate of removal of the'gas is much fasterthan when it is removed by being mixed with the liquid and pumped out ofthe impeller housing by means of the impeller.

As soon as the gas has been removed from chamber 10 and inlet 3 and anypipe connecting therewith, and replaced with liquid, impeller 30 pumpsthat liquid and discharges it through Venturi 12 along with the liquidbeing discharged therethrough from chamber 11. 1 In other words, at thattime two impellers are pumping liquid simultaneously.

The apparatus of Fig. 1 may also be considered as follows: A firstimpeller casing has walls 8 and 15, an inlet 6 and a discharge nozzle16, with an impeller 31 in the casing to discharge liquid under pressurethrough the nozzle. A second impeller casing has walls 7 and 15, aninlet and a discharge outlet 12 which surrounds, is aligned with andforms a chamber about the nozzle 16 of the first casing with an impeller30. The housing 1 forms a chamber which communicates with the dischargeoutlet 12 from the second casing and with the inlet 6 into the firstcasing. Liquid and gases discharged from that outlet may separate inthat chamber and the liquid is conducted into the inlet and in beingdischarged through the nozzle 16 induces a flow of fluid into the inlet5 of the second casing.

It will be understood from the foregoing description that during thepriming action one impeller pumps liquid and the other provides apassage for gas and vapor, and the liquid so pumped passes through a jetejector and induces flow of gas and vapor through said passage; and thatafter priming has been completed both impellers pump only liquid.

In the modification shown in Fig. 2 the housing 40 is adapted to containliquid, is provided wth an intake 41 to which a pipe may be connected ifdesired as at 42. The housing has an outlet 43 for gas and liquid, andis provided with packing 44, and a stuffing box 45 in one side-wallthrough which an impeller shaft 46 extends into the housing.

A casing 47 is disposed in the housing and communicates with inlet 41 onone side and with the interior of the casing on the other side as at 48.Thus the casing 47 may receive gas or liquid from outside of the housing40, and may also receive liquid from within the housing.

The opposite side-walls 49 and 50 constituting casing 47 convergingtoward their peripheries and define a peripheral outlet 51 of Venturiconfiguration.

Impeller shaft 46 which extends through packing 44 and the side-wall ofhousing 40 projects into casing 47 and is there connected to an impeller55. This impeller comprises a central partition plate 56 having impellerblades 57 on opposite sides thereof. Shroud rings 58 are attached to theedges of blades 57 and together with partition plate 56 defineperipheral outlets 59 and 60, the latter preferably being restricted andnozzle shaped. Both outlets 59 and 60 are positioned to deliver liquidinto Venturi 51.

When the pump of Fig. 2 is to prime, impeller shaft 46 is rotated andthe impeller pumps liquid in through inlet 48, out through nozzle 60 athigh velocity and thence out through Venturi 51. At the same time theother impeller provides a fluid path through the impeller from inlet 41to outlet 59. The flow of the high velocity liquid through Venturi 51acts as a jet ejector to induce the flow of gas and vapor through saidfluid path. As soon as the gas in inlet 41 and piping connected theretohas been exhausted and replaced by liquid, both sides of the impellerpump liquid through Venturi 51.

In the modification of the present invention shown in Fig. 3 the housing70 is provided to contain liquid and has an inlet 71 to be connected toa source of liquid through a pipe which may be attached, as at 72.Liquid and gas may escape from housing through outlet 73. Through onesidewall of housing 70 .an impeller shaft 74 extends and is fitted withpacking 75, and the packing gland 76.

A casing disposed within housing 70 comprises sidewalls 77 and 78 theformer being connected to the housing for communication with inlet 71,the latter having a central opening 79 through which liquid in thehousing may enter the casing. This casing is provided with a.circumferential volute chamber 80 having an outlet 81. An impeller ispositioned within the casing on the inner end of shaft 74. This impellercomprises a central wall 82, impeller blades 83 and 83a on oppositesides thereof and shroud rings 84 and 85 connected to blades 83 and 83a.Ring 84 has a central opening communicating with housing inlet 71 andring 85 has a central opening within opening 79 of the casing andcommunicating with liquid in housing 7 0. The partition wall 82 andshroud ring 85 converge toward each other and form nozzle 86 throughwhich liquid pumped by blades 83 may be discharged at high velocity.Shroud ring 84 and 82 form peripheral outlets 87 between blades 83a.Rings 84 and 85 extend outwardly beyond the outer periphery of centralwall 82 and are shaped to form a Venturi-like outlet 88 into which thenozzle 86 discharges and from which the liquid may pass out thru outlet81.

When the pump illustrated in Fig. 3 is to prime, shaft 74 is rotated.Impeller blades 83 pump liquid from within the housing through nozzles86 and Venturi 88 thereby creating a jet ejector effect on gas and vaporbetween blades 83a in inlet 71 and in any pipe line connected thereto,with resultant flow of gas and vapor thru outlets 87. As soon as the gashas been exhausted and replaced by liquid, blades 83a pump liquid fromoutside of the housing through inlet 71 and thus all the impeller bladesare pumping liquid into housing 70.

It will be understood that the clearance between the walls defining theimpeller intakes and the surrounding walls of the casing is small enoughto minimize the amount of pumped liquid which is returned to the intake,as is conventional practice.

It will be understood from the foregoing disclosure that gas isexhausted from the pump and the connections to a source of liquidoutside of the housing largely by the jet ejector principle ofoperation. Thus the evacuation of gas or the priming of the pump is verymuch faster than when it is accomplished by mixing the gas with liquidin the impeller chamber. It will also be understood that once the pumphas been primed, both impellers participate in the liquid pumping actionand while the effect is not twice as great as that of either impelleralone it is considerably greater than the pumping effect of only oneimpeller. Thus the present invention combines the rapid evacuatingaction of the jet ejector with the efficient liquid pumping action ofthe centrifugal pump. The invention comprises a new combination of partshaving this new operation and these new and hitherto unobtainableresults.

Having described this invention so that others may be able to understandand practice the same, I state that what I desire to secure by letterspatent is defined in what is claimed.

What is claimed is: I l. A self-priming centrifugal pump comprising afirst impeller casing having a chamber, a central inlet and an outerperipheral liquid pressure discharge nozzle, an impeller rotatablymounted in said casing for moving pressure liquid from said inletthrough said discharge nozzle, a second impeller casing having a centralinlet and a peripheral discharge outlet aligned with said dischargenozzle, said second impeller casing enclosing and forming a chamberabout said nozzle, a second impeller r0- tatably mounted in said secondchamber for moving fluid therethrough, means communicating with thedischarge outlet of the second casing and forming a liquid supplychamber for said first impeller about its central inlet, conduit meansforming an intake for liquid and vapor to said second casing and meansfor rotating said first and second impeller, whereby liquid dischargedthrough said nozzle entrains liquid and vapor in said second chamber todischarge therewith through said discharge outlet.

2. The combination of elements set forth in claim 1 in which the twosaid casings have a common wall.

3. The combination of elements set forth in claim 1 in which the saiddischarge nozzle of the first casing opens through a Wall which iscommon to both casings.

4. The combination of elements set forth in claim 1 10 in which the saidmeans includes a housing enclosing and forming a chamber about saidcasings.

5. The combination of elements set forth in claim 1 in which the saidmeans includes a housing enclosing said casings and having an inletpassage opening into the inlet 15 of said second casing.

6. The combination of elements set forth in claim 1 in which the saidimpellers are fixed to and are rotatable by a common shaft.

References Cited in the file of this patent UNITED STATES PATENTS

